Explanation:
The circled stars in the above picture are from a class that is hard to see
in the cosmos:
white dwarfs.
The entire photo covers a small region near the center of a
globular cluster known as M4. Researchers using
the
Hubble Space Telescope
discovered a large concentration of white dwarfs in M4. This was
expected - low mass stars, including the
Sun, are known to evolved to
the white dwarf stage. White dwarfs do not usually evolve further, they
just gradually cool down from their high temperatures. It is hoped that
studying how these stars cool could lead to a better understanding
of their ages, of the age of their parent globular cluster, and hopefully
even the age of our universe!